Package structure and method of forming the same

ABSTRACT

A package structure and a method of forming the same are provided. The package structure includes a die, an encapsulant, a redistribution layer (RDL) structure, a passive device, and a plurality of dummy items. The encapsulant laterally encapsulates the die. The RDL structure is disposed on the die and the encapsulant. The passive device is disposed on and electrically bonded to the RDL structure. The plurality of dummy items are disposed on the RDL structure and laterally aside the passive device, wherein top surfaces of the plurality of dummy items are higher than a top surface of the passive device.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of various electroniccomponents (i.e., transistors, diodes, resistors, capacitors, etc.). Forthe most part, this improvement in integration density has come fromcontinuous reductions in minimum feature size, which allows more of thesmaller components to be integrated into a given area. These smallerelectronic components also require smaller packages that utilize lessarea than previous packages. Some smaller types of packages forsemiconductor components include quad flat packages (QFPs), pin gridarray (PGA) packages, ball grid array (BGA) packages, and so on.Currently, integrated fan-out (InFO) packages are becoming increasinglypopular for their compactness.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1A to FIG. 1M are schematic cross-sectional views illustrating amethod of forming a package structure according to some embodiments ofthe disclosure.

FIG. 2A to FIG. 2E are partial cross-sectional views of FIG. 1M whichillustrates various examples of dummy item, according to someembodiments of the disclosure.

FIG. 3A is a top view of FIG. 1H, FIG. 3B is an enlarged view of aregion in FIG. 3A, and FIG. 1H is a cross-sectional view taken alongline I-I′ of FIG. 3B.

FIG. 4A to FIG. 4I are schematic cross-sectional views illustrating amethod of forming a package structure according to some otherembodiments of the disclosure.

FIG. 5 is a schematic cross-sectional view illustrating a packagestructure according to alternative embodiments of the disclosure.

FIG. 6A to FIG. 6E are partial cross-sectional views of FIG. 5 whichillustrates various examples of dummy item bonded to dummy pad,according to the alternative embodiments of the disclosure.

FIG. 7 is a schematic cross-sectional view illustrating a packagestructure according to alternative embodiments of the disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a second feature over or on a first feature in the description thatfollows may include embodiments in which the second and first featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the second and first features,such that the second and first features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath”, “below”, “lower”,“on”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the FIG.s. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe FIG.s. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Other features and processes may also be included. For example, testingstructures may be included to aid in the verification testing of the 3Dpackaging or 3DIC devices. The testing structures may include, forexample, test pads formed in a redistribution layer or on a substratethat allows the testing of the 3D packaging or 3DIC, the use of probesand/or probe cards, and the like. The verification testing may beperformed on intermediate structures as well as the final structure.Additionally, the structures and methods disclosed herein may be used inconjunction with testing methodologies that incorporate intermediateverification of known good dies to increase the yield and decreasecosts.

FIG. 1A to FIG. 1M are schematic cross-sectional views illustrating amethod of forming a package structure according to some embodiments ofthe disclosure.

Referring to FIG. 1A, a carrier 100 is provided. The carrier 100 may bea glass carrier, a ceramic carrier, or the like. In some embodiments,the carrier 100 has a de-bonding layer 101 formed thereon. Thede-bonding layer 101 is formed by, for example, a spin coating method.In some embodiments, the de-bonding layer 101 may be formed of anadhesive such as an Ultra-Violet (UV) glue, a Light-to-Heat Conversion(LTHC) glue, or the like, or other types of adhesives. The de-bondinglayer 101 is decomposable under the heat of light to thereby release thecarrier 100 from the overlying structures that will be formed insubsequent processes.

A dielectric layer 102 is formed on the de-bonding layer 101 over thecarrier 100. In some embodiments, the dielectric layer 102 may be apolymer layer including polymer materials, but the disclosure is notlimited thereto. Alternatively, the dielectric layer 102 may includeinorganic dielectric materials. For example, the dielectric layer 102may include polybenzoxazole (PBO), polyimide (PI), benzocyclobutene(BCB), ajinomoto buildup film (ABF), solder resist film (SR), or thelike, a nitride such as silicon nitride, an oxide such as silicon oxide,an oxynitride such as silicon oxynitride, phosphosilicate glass (PSG),borosilicate glass (BSG), boron-doped phosphosilicate glass (BPSG), orthe like, or combinations thereof. The dielectric layer 102 is formed bya suitable fabrication technique such as spin-coating, lamination,deposition such as chemical vapor deposition (CVD), or the like.

Still referring to FIG. 1A, a plurality of conductive vias 103 areformed on the dielectric layer 102. In some embodiments, the conductivevias 103 may also be referred to as through integrated fan-out vias(TIVs). The conductive via 103 includes copper, titanium, nickel,solder, alloys thereof, or the like or combinations thereof. In someembodiments, each of the conductive vias 103 includes a seed layer and aconductive post formed thereon (not individually shown). In other words,the seed layer is in contact with and vertically between the dielectriclayer 102 and the conductive post. The seed layer may be a metal seedlayer such as a copper seed layer. In some embodiments, the seed layerincludes a first metal layer such as a titanium layer and a second metallayer such as a copper layer over the first metal layer. The conductivepost may include copper or other suitable metals. However, thedisclosure is not limited thereto.

In some embodiments, the conductive vias 103 may be formed by thefollowing processes: a seed material layer is firstly formed on thedielectric layer 102 by a sputtering process, a patterned mask layersuch as a patterned photoresist is formed on the seed material layer.The patterned mask layer includes openings exposing portions of seedmaterial layer at the locations where the conductive vias 103 are to beformed. The conductive posts are then formed on the seed material layerexposed by the patterned mask layer. The patterned mask layer isstripped, and the portions of the seed material layer not covered by theconductive posts are removed. As such, the conductive posts and theunderlying seed layers constitute the conductive vias 103. In some otherembodiments, the conductive vias 103 further include a barrier layer(not shown) under the seed layer to prevent metal diffusion. Thematerial of the barrier layer includes, for instance, metal nitride suchas titanium nitride, tantalum nitride, or a combination thereof.

Referring to FIG. 1B, a die 110 is mounted to the carrier 100 by pickand place processes, for example. In some embodiments, the die 110 isattached to the dielectric layer 102 through an adhesive layer 104 suchas a die attach film (DAF), silver paste, or the like. In someembodiments, the die 110 is one of a plurality of dies cut apart from awafer, for example. The die 110 may be an application-specificintegrated circuit (ASIC) chip, an analog chip, a sensor chip, awireless and radio frequency chip, a voltage regulator chip, a memorychip, or any other suitable type of die. The number of the die 110 shownin FIG. 1C is merely for illustration, and the disclosure is not limitedthereto. In some embodiments, a plurality of dies 110 may be mountedover the carrier 100, and the plurality of dies 110 may be the sametypes of dies or the different types of dies.

The die 110 is disposed between the TIVs 103, that is, the TIVs 103 areaside or around the die 110. In some embodiments, the die 110 mayinclude a substrate 105, a plurality of conductive pads 106, and apassivation layer 107. In some embodiments, the substrate 105 is made ofsilicon and/or other semiconductor materials. Alternatively oradditionally, the substrate 105 includes other elementary semiconductormaterials such as germanium, gallium arsenic, or other suitablesemiconductor materials. In some embodiments, the substrate 105 mayfurther include other features such as various doped regions, a buriedlayer, and/or an epitaxy layer. Moreover, in some embodiments, thesubstrate 105 is made of an alloy semiconductor such as silicongermanium, silicon germanium carbide, gallium arsenic phosphide, orgallium indium phosphide. Furthermore, the substrate 105 may be asemiconductor on insulator such as silicon on insulator (SOI) or siliconon sapphire.

In some embodiments, a plurality of devices (not shown) are formed inand/or on the substrate 105. The devices may be active devices, passivedevices, or combinations thereof. In some embodiments, the devices areintegrated circuit devices. The devices are, for example, transistors,capacitors, resistors, diodes, photodiodes, fuse devices, or the like,or combinations thereof.

In some embodiments, an interconnection structure (not specificallyshown) is formed over the devices on the substrate 105. Theinterconnection structure may include a plurality of conductive featuresembedded in a dielectric structure, so as to electrically connectdifferent devices in and/or on the substrate 105 to form a functionalcircuit. In some embodiments, the dielectric structure includes aninter-layer dielectric layer (ILD) and one or more inter-metaldielectric layers (IMD). The conductive features may include multiplelayers of conductive lines and conductive plugs (not shown). Theconductive plugs include contact plugs and via plugs. The contact plugsare located in the ILD to connect the metal lines to the devices. Thevia plugs are located in the IMDs to connect the metal lines indifferent layers. The dielectric structure includes suitable dielectricmaterials such as silicon oxide, silicon nitride, silicon oxynitride,low-k dielectric materials, or combinations thereof. The metallizationfeatures include metal, metal alloy or a combination thereof, such astungsten (W), copper (Cu), copper alloys, aluminum (Al), aluminumalloys, or combinations thereof.

The conductive pads 106 may be or electrically connected to a topconductive feature of the interconnection structure, and furtherelectrically connected to the devices formed on the substrate 105through the interconnection structure. The material of the conductivepads 106 may include metal or metal alloy, such as aluminum, copper,nickel, or alloys thereof.

The passivation layer 107 is formed over the substrate 105 and partiallycovers the conductive pads 106. Portions of the conductive pads 106 areexposed by the passivation layer 107 and serve as external connectionsof the die 110. The passivation layer 107 includes an insulatingmaterial such as silicon oxide, silicon nitride, polymer, or acombination thereof. The polymer may include PBO, PI, BCB, the like orcombinations thereof.

In some embodiments, the die 110 is a sensor chip and includes aplurality of sensing regions 108. The sensing regions 108 may be pixelregions in some embodiments. The sensing regions 108 may extend from thetop surface of the passivation layer 107 to the device layer on thesubstrate 105, but the disclosure is not limited thereto. In someembodiments, the sensing regions 108 are disposed between the conductivepads 106, for example. It is noted that, the shape, size and locationsof the sensing regions 108 shown in the figures are merely forillustration, and the disclosure is not limited thereto.

In the embodiments in which the die 110 is a sensor chip, the die 110may further include a sacrificial film 109 formed over the substrate 105and covering the sensing regions 108. In some embodiments, thesacrificial film 109 overlays a portion of passivation layer 107 withoutcovering the conductive pads 106, that is, the width of the sacrificialfilm 109 may be less than the width of the die 110, but the disclosureis not limited thereto. In alternative embodiments, the sacrificial film109 may further extend to cover the conductive pads 106. For example,the sacrificial film 109 may completely cover the passivation layer 107and the conductive pads 106. The width of the sacrificial film 109 maybe substantially equal to the width of the die 110. In some embodiments,the material of the sacrificial film 109 is different from the materialsof the passivation layer 107 and the subsequently formed encapsulant.For example, the sacrificial film 107 may include a polymer such aspolybenzoxazole (PBO), polyimide (PI), benzocyclobutene (BCB), acombination thereof, or the like, but the disclosure is not limitedthereto. In some embodiments, the die 110 is free of a connector (e.g.,metal pillar) on the conductive pads 106, but the disclosure is notlimited thereto.

Referring to FIG. 1C, an encapsulant material layer 112 is then formedover the carrier 100 to encapsulate the die 110 and the conductive vias103. In some embodiments, the encapsulant material layer 112 includes amolding compound, a molding underfill, a resin such as epoxy, acombination thereof, or the like. In some other embodiments, theencapsulant material layer 112 includes a photo-sensitive material suchas polybenzoxazole (PBO), polyimide (PI), benzocyclobutene (BCB), acombination thereof, or the like. In alternative embodiments, theencapsulant material layer 112 includes nitride such as silicon nitride,oxide such as silicon oxide, phosphosilicate glass (PSG), borosilicateglass (BSG), boron-doped phosphosilicate glass (BPSG), a combinationthereof, or the like. In some embodiments, the encapsulant materiallayer 112 includes a molding compound which is a composite materialincluding a base material (such as polymer) and a plurality of fillersdistributed in the base material. The filler may be a single element, acompound such as nitride, oxide, or a combination thereof. The fillersmay include silicon oxide, aluminum oxide, boron nitride, alumina,silica, or the like, for example. The cross-section shape of the fillermay be circle, oval, or any other suitable shape.

In some embodiments, the encapsulant material layer 112 is formed by anover-molding process, such that the encapsulant material layer 112 has atop surface higher than top surfaces of the conductive vias 103 and thedie 110. In other words, the encapsulant material layer 112 encapsulatessidewalls and top surfaces of the die 110 and the conductive vias 103.

Referring to FIG. 1D, thereafter, a planarization process is performedto remove a portion of the encapsulant material layer 112 to expose theconductive vias 103 and the sacrificial film 109, and an encapsulant 112a is formed. The planarization process includes a chemical mechanicalpolishing (CMP) process, for example. In some embodiments, a portion ofthe sacrificial film 109 and/or portions of the conductive vias 103 mayalso be removed by the planarization process. After the planarizationprocess is performed, the top surfaces of the encapsulant 112 a, theconductive vias 103 and the sacrificial film 109 are substantiallycoplanar with each other. In some embodiments in which the sacrificiallayer 109 partially covers the passivation layer 107, a portion of theencapsulant 112 a is located on the die 110 to encapsulate andphysically contact top surfaces of portions of the passivation layer 107and the top surfaces of the conductive pads 106 uncovered by thesacrificial layer 109. In alternative embodiments in which thesacrificial layer 109 completely covers the top surfaces of thepassivation layer 107 and the conductive pads 106, the encapsulant 112 ais laterally aside the die 110 (as shown in FIG. 7 ).

Referring to FIG. 1D and FIG. 1E, the sacrificial film 109 is removed toexpose the sensing regions 108 of the die 110. The sacrificial film 109may be removed by a suitable technique such as an etching process, alaser irradiation process, or the like. The etching process may includedry etching, wet etching or a combination thereof.

Referring to FIG. 1E, in some embodiments, after the sacrificial film109 is removed, a portion of the passivation layer 107 is exposed, whilethe other portion of the passivation layer 107 and the conductive pads106 are covered by the encapsulant 112. The top surfaces of thepassivation layer 107 and the conductive pads 106 constitute the firstsurface FS of the die 110. The first surface FS may also be referred toas a front surface or an active surface of the die 110. In theembodiments, the first surface FS of the die 110 is lower than the topsurface of the encapsulant 112 a and the top surfaces of the conductivevias 103, and a portion of the first surface FS of the die 110 isencapsulated by the encapsulant 112 a. The die 100 has a second surfaceBS opposite to the first surface FS. The second surface BS is a bottomsurface of the substrate 105, and may also be referred to as a backsurface of the die 110.

Still referring to FIG. 1E, a recess 115 is formed at the positionpreviously occupied by the removed sacrificial film 109. The recess 115is located over the die 110 and within the encapsulant 112 a, and aportion of the sidewall of the encapsulant 112 a is exposed by therecess 115. In other words, the recess 115 is defined by a portion ofthe first surface FS of the die 110 and the sidewall of the encapsulant112 a.

Referring to FIG. 1F, a redistribution layer (RDL) structure 120 isformed on the die 110, the conductive vias 103 and the encapsulant 112a, and electrically connected to the die 110 and the conductive vias103. The sensing regions 108 of the die 110 may be exposed by the RDLstructure 120. In some embodiments, the RDL structure 120 is alsoreferred to as a “front-side RDL structure” formed on the front side ofthe die 110. Herein, the term “front-side” refers to a side close to theconductive pads 106 of the die 110.

In some embodiments, the RDL structure 120 includes multi-layers ofpolymer layers and redistribution layers alternatively formed on oneanother. For example, the RDL structure 120 includes polymer layers PM1,PM2, and redistribution layers RDL1, RDL2. The number of the polymerlayers or the redistribution layers shown in FIG. 1F is merely forillustration, and the disclosure is not limited thereto. In someembodiments, each of the polymer layers PM1, PM2 includes aphoto-sensitive material such as polybenzoxazole (PBO), polyimide (PI),benzocyclobutene (BCB), a combination thereof or the like, but thedisclosure is not limited thereto. Each of the redistribution layersRDL1 and RDL2 includes conductive materials. The conductive materialsinclude metal such as copper, nickel, titanium, a combination thereof orthe like. In some embodiments, each of the redistribution layers RDL1and RDL2 includes a seed layer (not shown) and a metal layer formedthereon (not shown). The seed layer may be a metal seed layer such as acopper seed layer. In some embodiments, the seed layer includes a firstmetal layer such as a titanium layer and a second metal layer such as acopper layer over the first metal layer. The metal layer may includecopper or other suitable metals.

In some embodiments, the redistribution layer RDL1 penetrates throughthe polymer layer PM1 and the encapsulant 112 a to connect to theconductive vias 103 and the conductive pads 106 of the die 110. Theredistribution layer RDL2 penetrates through the polymer layer PM2 toconnect to redistribution layer RDL1. A portion of the RDL structure120, such as a portion of the polymer layer PM1 may fill into the recess115 and covers a portion of the top surface of the passivation layer107. In some embodiments, the RDL structure 120 has an opening OPoverlapped and in spatial communication with the recess 115, so as toexpose the sensing regions 108 of the die 110. The opening OP may bedefined by a portion of front surface FS of the die 110 and the surface(i.e., inner sidewall or inner surface) IS of the RDL structure 120. Itis noted that, although the RDL structure 120 is shown to have twoseparate parts on opposite sides of the opening OP in thecross-sectional view FIG. 1F, the RDL structure 120 is actually acontinuous structure. When viewed in a top view, the RDL structure 120may be a continuous structure with the opening OP disposed in a centerregion thereof.

In some embodiments, the inner surface IS of the RDL structure 120 maybe configured as a stepped shape. In other words, a portion (e.g., edgeportion) of the RDL structure 120 is step shaped. The inner surface ISmay include a first inner sidewall landing on the die 110, a secondinner sidewall over the first inner sidewall, and a substantially planarsurface connecting the first inner sidewall and the second innersidewall. The first inner sidewall is laterally shift from the secondinner sidewall and more closer to a center of the die 110 than thesecond inner sidewall to the center of the die 110 in a horizontaldirection. The planar surface may be lower than, substantially coplanarwith or higher than the top surface of the polymer layer PM1. The firstinner sidewall may include at least a portion of an inner sidewall ofthe polymer layer PM1. The second inner sidewall may include at least aportion of an inner sidewall of the polymer layer PM2. In someembodiments, a portion of the polymer layer PM1 may laterally protrudefrom the polymer layer PM2 and/or another portion of the polymer layerPM1. However, the disclosure is not limited thereto. In alternativeembodiments, the inner surface (i.e., inner sidewall) of the RDLstructure 120 may be substantially straight or inclined.

In some embodiments, the RDL structure 120 may be formed by thefollowing processes: a first polymer material layer is formed over thecarrier 100 to cover die 110 and the encapsulant 112 a through asuitable technique such as spin coating, chemical vapor deposition(CVD), plasma-enhanced chemical vapor deposition (PECVD), lamination orthe like. Thereafter, the redistribution layer RDL1 is formed on andpenetrating through the first polymer material layer and the encapsulant112 a to connect to the conductive vias 103 and the conductive pads 106.The forming method of the redistribution layer RDL1 may include physicalvapor deposition (PVD) such as sputtering process, and electroplatingprocess. The formation of the redistribution layer RDL1 may avoid theregion directly over the sensing region 108 of the die 110. Thereafter,processes for forming the polymer material layer and redistributionlayer are repeated to form a second polymer material layer and theredistribution layer RDL2. The first polymer material layer and/or thesecond polymer material layer may fill in the recess 115 and overlay thesensing regions 108. In some embodiments, thereafter, the second andfirst polymer material layers are patterned to form the polymer layersPM1, PM2 having the opening OP, thereby exposing the sensing regions108. The patterning method may include exposure and development process,laser drilling process, or the like, or combinations thereof. In someother embodiments, the pattering of the polymer material layer may beperformed before the formation of the corresponding redistributionlayer.

In some embodiments, the polymer layer PM1 is disposed on theencapsulant 112 a and may partially fill into the recess 115 (FIG. 1E).The polymer layer PM1 may cover the top surface of the encapsulant 112a, a portion of the front surface FS of the die 110, and/or portions ofthe top surfaces of the conductive vias 103. In some embodiments, aportion of the polymer layer PM1 fills into the recess 115 to cover thesidewall (i.e., inner sidewall) of the encapsulant 112 a. The topcorners of the encapsulant 112 a may be covered by the polymer layerPM1. In some embodiments, the polymer layer PM1 may be not filled in therecess 115, and the inner sidewall of the polymer layer PM1 may besubstantially aligned with or laterally shifted from the inner sidewallof the encapsulant 112 a.

The redistribution layer RDL1 penetrates through the polymer layer PM1and the encapsulant 112 a to electrically connect to the conductive pads106 of the die 110 and the conductive vias 103. In some embodiments, theredistribution layer RDL1 includes a plurality of vias V1 and V2 andtraces T1 electrically connected to each other. The traces T1 arelocated on and extending on the top surface of the polymer layer PM1.The vias V1 penetrate through the polymer layer PM1 and the underlyingencapsulant 112 a, so as to connect the traces T1 to the conductive pads106 of the die 110. The vias V2 penetrate through the polymer layer PM1,so as to connect the traces T1 to the conductive vias 103. The height ofthe via V1 is larger than the height of the via V2, and the bottomsurface of the via V1 is lower than the bottom surface of the via V2.Upper portions of the vias V1 are embedded in polymer layer PM1, whilebottom portions of the vias V1 are laterally encapsulated by theencapsulant 112 a and laterally aside the conductive vias 103.

The polymer layer PM2 is disposed on the polymer layer PM1 to cover theredistribution layer RDL1. In some embodiments, a portion of the polymerlayer PM2 may be laterally surrounded by the vias V1 and may have abottom surface (i.e., the bottommost surface of the polymer layer PM2)lower than a top surface of the encapsulant 112 a. However, thedisclosure is not limited thereto. The bottommost surface of polymerlayer PM2 may be higher than or substantially coplanar with the topsurface of the encapsulant 112 a, which is at least partially dependingon the configuration of the via V1. In some embodiments, theredistribution layer RDL2 may be a conductive via or conductive pillarprotruding from the top surface of the polymer layer PM2 for furtherelectrical connection. The cross-sectional shape of the redistributionlayer RDL2 may be inverted trapezoid, square, rectangle, or the like, orany other suitable shape.

Referring to FIG. 1G, in some embodiments, adhesive materials 124 andflux materials 125 are applied onto the RDL structure 120. In someembodiments, the adhesive materials 124 and the flux materials 125 maybe formed of a same material and formed by a same printing process. Forexample, the adhesive materials 124 and the flux materials 125 includeepoxy flux which has adhesiveness as well as the function of servingflux during soldering process. The printing process may be formed by thefollowing processes: a stencil 122 is placed onto the RDL structure 120.The stencil 122 has a plurality of openings 123 a and 123 b exposingportions of the top surface of the RDL structure 120. In someembodiments, the openings 123 a expose portions of the top surface ofthe polymer layer PM2, while the openings 123 b expose theredistribution layer RDL2 and portions of the polymer layer PM2 adjacentto the redistribution layer RDL2. The printing process is performedusing the stencil 122, such that the adhesive materials 124 and fluxmaterials 125 are applied/printed on the polymer layer PM2 and theredistribution layer RDL2 exposed by the openings 123 a and 123 b of thestencil 122, respectively. However, the disclosure is not limitedthereto. In alternative embodiments, the adhesive materials 124 and theflux materials 125 may be formed of different materials and formed byseparate printing processes.

Referring to FIG. 1H, in some embodiments, a plurality of dummy items126 are attached to the polymer layer PM2 of the RDL structure 120, anda plurality of passive devices 130 are electrically bonded toredistribution layers RDL2 of the RDL structure 120. The passive devices130 are further electrically coupled to the die 110 through the RDLstructure 120. The passive device 130 may be integrated passive device(IPD), surface mount device (SMD), or combinations thereof, but thedisclosure is not limited thereto. In some embodiments, the passivedevice 130 includes connectors 128 electrically connected to conductivepads 127 thereof. The conductive pads 127 may include metal, such asaluminum, copper, alloys thereof, or any other suitable metallicmaterial. The connectors 128 may be solder bumps, solder balls or othersuitable metallic connectors. In some embodiments, the connectors 128may also be referred to as conductive terminals of the passive device130. The connectors 128 are electrically bonded to the redistributionlayers RDL2.

In some embodiments, the mounting of the dummy items 126 and the passivedevices 130 includes: placing the dummy items 126 onto the adhesivematerials 124, placing the passive device 130 onto the redistributionlayer RDL2, and the flux material 125 may be pushed outward to surroundthe connectors 128 and/or the conductive pads 127 of the passive device130 and the redistribution layer RDL2; thereafter, a reflow process isperformed. As such, adhesive layers 124 a are formed between the dummyitems 126 and the polymer layer PM2 of the RDL structure 120. In otherwords, the dummy items 126 are attached to the RDL structure 120 throughthe adhesive layers 124 a. During the reflow process, a portion of theflux material 125 is reacted with connectors 128 and/or theredistribution layer RDL2 to facilitate the bonding process, and theother portion of the flux material 125 is unreacted and remained as afilling layer 125 a. The filling layer 125 a may also be referred to asa flux residue. As shown in FIG. 1H, the filling layer 125 a is disposedto fill the space between the passive device 130 and laterallysurrounding the connectors 128 and/or the conductive pads 127 of thepassive device 130 and may further laterally surrounding a portion ofthe redistribution layer RDL2 of the RDL structure 120. In someembodiments, the adhesive layer 124 a and the filling layer 125 a havesizes and/or shapes that are different from the adhesive material 124and the flux material 125, which may be caused by the mechanical forceduring the placement of the dummy items 126 and the passive device 130and/or the reflow process.

In some embodiments in which the adhesive materials 124 and the fluxmaterials 125 are formed of the same material, the material performsdifferent functions during the mounting of the dummy items 126 and thepassive devices 127. The mounting of the dummy items 126 uses theadhesiveness of the material for attaching the dummy items 126, whilethe mounting of the passive device 130 uses the material as a flux tofacilitate the bonding process.

It is noted that, the mounting process shown in FIG. 1G to FIG. 1H ismerely for illustration, and the disclosure is not limited thereto.Other suitable mounting process may also be used. For example, thepassive devices 130 may be firstly bonded to the RDL structure 120, andthe flux residue may be removed after the bonding process. An underfilllayer may further be disposed to fill the space between the passivedevice 130 and the RDL structure 120. The location of the underfilllayer is substantially the same as the location of the filling layer 125a shown in FIG. 1H. Thereafter, the dummy items 126 may be attached tothe RDL structure 120 by an adhesive layer such as a die attach film(DAF), non-conductive film (NCF), non-conductive paste (NCP), silverpaste, or the like, or other types of adhesives. The adhesive layer maybe initially applied on the bottom surface of the dummy item 126 andthen attached to the RDL structure 120.

Still referring to FIG. 1H, in the embodiments of the disclosure, thedummy items 126 are formed to have top surfaces higher than the topsurfaces of the passive devices 130. In some embodiments, the height H1defined by the vertical distance from the top surface of the dummy item126 to the top surface of the polymer layer PM2 is larger than theheight H4 defined by the vertical distance from the top surface of thepassive device 130 to the top surface of the polymer layer PM2. Theheight H1 is substantially equal to the sum of the height H2 of thedummy item 126 and the height (i.e., thickness) H3 the adhesive layer124 a. In some embodiments, the height H4 may be substantially equal tothe sum of the height of the passive device 130 and the height of theportion of the redistribution layer RDL2 protruding above the topsurface of the polymer layer PM2. For example, the height H4 of thepassive device 130 ranges from 50 μm to 650 μm. The height H2 of thedummy item 126 may range from 75 μm to 760 μm. The height H3 of theadhesive layer 124 a may be greater than zero. In some embodiments, thewidth W of the dummy item 126 may be larger than 50 μm. If the width Wis very small, such as less than 50 μm, the dummy item which has thesmall width and relatively large height may be fragile and easilycollapsed. In other words, the dummy item 126 has sufficient dimensionto be a stable structure.

The dummy items 126 may be formed of various suitable materials, such asconductive material, dielectric material, semiconductor material, or anyother suitable material, or combinations thereof. Further, the dummyitems 126 may have any suitable shape, as long as the height H1 islarger than the height H4. Throughout the specification, the term “dummyitem” refers to the component that is electrically floating. In otherwords, the dummy items 126 are electrically isolated from the RDLstructure 120, the passive device 130, the die 110 and the conductivevias 103.

FIG. 2A to FIG. 2E illustrate some examples of the dummy item 126according to some embodiments of the disclosure.

Referring to FIG. 1H and FIG. 2A, in some embodiments, the dummy item126 may be a metal pillar, such as copper stud bump, and may also bereferred to as a dummy pillar. In alternative embodiments, the dummyitem 126 is a dummy die including semiconductor materials, such assilicon. The dummy die may be singulated from a bare wafer and is freeof devices therein. The cross-sectional shape of the dummy item 126 maybe square, rectangular, or the like. The adhesive layer 124 a isdisposed between the dummy item 126 and the polymer layer PM2. Theadhesive layer 124 a covers the bottom surface of the dummy item 126 andmay further extend to cover (e.g., partially cover) sidewalls of thedummy item 126. The sidewalls of the adhesive layer 124 a may besubstantially straight or inclined.

Referring to FIG. 2B, in some embodiments, the dummy item 126 mayinclude a metal pillar 126 a and a cap 126 b on the metal pillar 126 a.For example, the metal pillar 126 a may be a copper stud bump, and thecap 126 b may be a conductive cover such as a solder cover, or adielectric cover. Other suitable materials may also be used. The cap 126b may surround and cover sidewalls and top surface of the metal pillar126 a. The cross-sectional shape of the metal pillar 126 a may besquare, rectangular, the like or any other suitable shape. The outerprofile of the cap 126 b may be rounded, circular, oval, or the like, orany other suitable shape.

Referring to FIG. 2C, in some embodiments, the dummy item 126 includes aconductive core 126 a and a cap on the 126 b covering on the conductivecore 126 a. The conductive core 126 a may be a metal core such as acopper core ball. The cross-sectional shape of the conductive core 126 amay be circular, oval, or the like. The cap 126 b may be a conductivecap such as a solder cap, but the disclosure is not limited thereto. Thecap 126 b may also be a dielectric cap in some other embodiments. Theouter profile of the cap 126 b is substantially the same as thosedescribed in FIG. 2C.

Referring to FIG. 2D, in some embodiments, the dummy item 126 may be aconductive ball, such as solder ball.

Referring to FIG. 2E, in some embodiments, the dummy item 126 mayinclude a surface mount device (SMD) or IPD. For example, a SMD is usedas the dummy item 126, and the SMD may be a resistor including a bodyportion and solder layers covering sidewalls and portions of the topsurface and bottom surface of the body portion. The adhesive layer maycover and in contact with portions of the solder layers and a portion ofthe bottom surface of the body portion uncovered by the solder layers.

It is noted that, the various types of dummy items 126 described withrespect to FIG. 2A to FIG. 2E are merely for illustration, and thedisclosure is not limited thereto.

Referring back to FIG. 1H, in some embodiments, a plurality of dummyitems 126 are formed on the RDL structure 120. The plurality of dummyitems 126 may be the same types of pillars or different types of dummyitems, and each of the dummy items 126 may be selected from thosedescribed in FIG. 2A to FIG. 2E or any other suitable types of dummyitems.

FIG. 3A is a top view illustrating a distribution of the dummy items 126on the RDL structure 120 over the carrier 100. FIG. 3B is an enlargedview of a region A1 of FIG. 3A. FIG. 1H is a cross-sectional view takenalong I-I′ line of FIG. 3B. Referring to FIG. 1H, FIG. 3A and FIG. 3B,in some embodiments, a plurality of package regions PKR are disposedover the carrier 100. The package regions PKR are the regions withinwhich package structures are to be formed. The package regions PKR arespaced apart from each other by scribe lines (or referred to as scriberegions) SL therebetween. FIG. 3B illustrates a top view of one of theplurality of package regions PKR, and FIG. 1H illustrates across-sectional view of an intermediate package structure formed in oneof the plurality of package regions PKR. In some embodiments, thestructures formed in different package regions PKR are substantially thesame or similar.

In some embodiments, the dummy items 126 are formed within packageregions PKR and are not formed in the scribe regions SL, but thedisclosure is not limited thereto. When viewed in a top view, the dummyitems 126 may be square as shown in FIG. 3A and FIG. 3B, but thedisclosure is not limited thereto. The top views of the dummy items mayalso be rectangular, circular, oval, or any other suitable shaped. Insome embodiments, the plurality of dummy items 126 are arranged in anarray including a plurality of rows and columns. Alternatively, thedummy items 126 may be randomly arranged over the RDL structure 120. Insome embodiments, each of the passive devices 130 has one or more dummyitem 126 disposed adjacent thereto, but the disclosure is not limitedthereto. In some embodiments, the dummy items 126 may be aligned with orstaggered with the passive devices 130 in a same row or column. In someembodiments, some of the dummy items 126 may be disposed at edgeportions of the package region PKR and may be arranged as a ring. Insome embodiments, some of the dummy items 126 may be arranged at orclose to center portions of the package region PKR and may surround theopening OP. It is noted that, the distribution of the dummy items 126shown in FIG. 3A and FIG. 3B is merely for illustration, and thedisclosure is not limited thereto. The advantages of the dummy items 126will be described below.

Referring to FIG. 1I, a tape 132 is placed on the intermediate structure50 formed in FIG. 1H. The tape 132 is an adhesive tape for attaching thestructure 50 to a table in subsequent processes. In some embodiments,the tape 132 is a soft tape and its shape on the structure 50 isdependent on the components attached thereto. In some embodiments, thedummy pillars 126 are configured to lift/support the tape 132 to preventthe tap 132 from sealing the intermediate structure 50.

Referring to FIG. 1I, FIG. 3A, and FIG. 3B, the tape 132 is in contactwith the dummy items 126 and may partially contact the passive devices130. In the embodiments, the number of dummy items 126 is sufficientenough to lift the tape 132, thereby preventing the tape 132 fromcompletely sealing the intermediate structure 50. Further, sufficientheight and width of the dummy items may also help to lift the tape 132.As a result, a space between the tape 132 and the intermediate structure50 is in spatial communication with the outer atmosphere (such asatmosphere in a process chamber) that is out of the space. Therefore,the dummy items 126 create air paths allowing the airs in the spacebetween the tape 132 and the structure 50 to flow out of the space, forexample, during subsequent process where the process chamber need to bevacuumed, some of the air paths are schematically and illustrativelyshown as the arrows AP in FIG. 3A and FIG. 3B. In some embodiments, thepassive devices 130 also help to create the air paths. The number,sizes, and distribution of the dummy items 126 are not limited to thatare shown in FIG. 3A and FIG. 3B, as long as the dummy items 126 canlift the tape 132 to create the air path.

Referring to FIG. 1I, in some embodiments, the tape 132 may be separated(e.g., completely separated) from the top surface of the polymer layerPM2. the sidewalls of the RDL structure 120 and/or the front surface FSof the die 110. In some other embodiments, the tape 132 may also have asmall portion that is in contact with the polymer layer PM2 and/or thefront surface FS of the die 110, as long as air between the tape 132 andthe intermediate structure 50 is not sealed, and there has air path forair between the tape 132 and the intermediate structure 50 to flow out.

Referring to FIG. 1I and FIG. 1J, the intermediate structure 50 isflipped upside down and attached to a table 134 through the tape 132.The table 134 may be a stage (e.g., wafer stage) or a platform in achamber of process tool. Thereafter, the carrier 100 is de-bonded fromthe intermediate structure 50. In some embodiments, the de-bonding layer101 is decomposed under the heat of light, and the carrier 100 is thenreleased. After the carrier 100 is released, the dielectric layer 102 isexposed.

Referring to FIG. 1K, in some embodiments, the dielectric layer 102 isthen patterned to form a plurality of openings 136 therein. The openings136 penetrate through the dielectric layer 102 and expose the pluralityof conductive vias 103. In some embodiments, the patterning of thedielectric layer 102 includes performing a laser drilling process toremove portions of the dielectric layer 102 directly over the conductivevias 103. Thereafter, a plasma cleaning process is performed to cleanthe surfaces of the dielectric layer 102 and/or the exposed conductivevias 103. In some embodiments, before performing the plasma cleaningprocess, the process chamber may be vacuumed, during which airs in thespace between the tape 132 and the intermediate structure 50 may flowout of the space through the above-described air paths (shown as arrowsAP in FIG. 3A and FIG. 3B) created by the dummy items 126.

Still referring to FIG. 1K, after the plasma cleaning process isperformed, a plurality of connectors 138 are formed on the dielectriclayer 102 and filling into the openings 136 to electrically connected tothe conductive vias 103. The connectors 138 may be conductive balls,micro bumps, or the like, or combinations thereof. In some embodiments,the connectors 138 are solder balls formed by a suitable technique, suchas ball mounting process, or a printing process followed by a reflowprocess. The connectors 138 are electrically connected to the die 110through the conductive vias 103 and the RDL structure 120.

Still referring to FIG. 1K, during the above processes where theintermediate structure 50 is placed on the table 134, the tape 132 isdisposed between the intermediate structure 50 and the table 134, and incontact with the dummy items 126 and the passive devices 130. In someembodiments, portions P1 of the tape 132 attaching to the passivedevices 130 are not in contact with the table 134 and are separated fromthe table 134 by a non-zero distance, while portions P2 of the tape 132are disposed between and in physical contact both of the dummy items 132and the table 134.

The configuration of the dummy items 126 has various advantages. In theembodiments, since the dummy items 126 create air paths allowing theairs between the tape 132 and the structure 50 to flow out, airs in thespace between the tape 132 and the structure 50 are in spatialcommunication with the outer atmosphere in the process chamber, that is,the air pressure between the tape 132 and the structure 50 issubstantially the same as the outer atmospheric pressure. As such, aplurality of potential issues might happen during the vacuuming andplasma process can be prevented. For example, if there has no dummy itemformed on the RDL structure 120 to create the air path, the tape 120 mayseal the structure 50. In other words, the air in the space between thetape 132 and the structure 50 may be sealed and cannot flow out. Assuch, during the vacuuming process, the sealed air between the tap 132and the structure 50 intended to flow out may push the tape and tapearcing issue may happen. Protrusions or tips may be formed in the tape132 when pushed by the sealed air, or the tape 132 may be broken by thesealed air intended to flow out. The protrusions or tips or brokenportions of the tape 132 may also be referred to as defect regions ofthe tape 132. Thereafter, during the plasma cleaning process, the defectregions of the tape 132 are prone to be heated by the plasma or reactwith the plasma, which may cause the tape to burn or damage, therebyadversely affecting the performing of the subsequent processes. In theembodiments of the disclosure, since the dummy items 126 are formed tocreate the air paths, the above-described issues are prevented.

On the other hand, through forming the dummy items 126 higher than thepassive devices 130, the dummy items 126 are closer to the table 134than the passive devices 130, and the passive device 130 is not directlyattached to the table 134 through the tape 132. Instead, the passivedevice 130 with the tape 132 attached thereon overhangs the table 134and separate from the table 134 by non-zero distance, which may avoidthe stress applied on the passive devices 130 from the table 134,thereby protecting the passive devices 130 from being damaged.

As such, a plurality of package structures PKG1 are thus formed in theplurality of package regions PKR (FIG. 3A). It is noted, FIG. 1A to FIG.1K shows the formation of one package structure PKG1 for illustration.It should be understood that a plurality of package structures PKG1 areformed side by side over the table 134, as shown in FIG. 1L and FIG. 3A.The number of the package structures PKG1 that are formed is not limitedin the disclosure.

Referring to FIG. 1L, a singulation process is then performed toseparate the package structures PKG1 through the scribe lines SL. Thesingulation process may include a die saw process, a laser dicingprocess, the like or combinations thereof.

Referring to FIG. 1L and FIG. 1M, the singulated package structure PKG1is removed from the table 134, and the tape 132 is removed. As such, thefabrication of the package structure PKG1 is completed.

Referring to FIG. 1M, in some embodiments, the package structure PKG1includes the die 110, the conductive vias 103, the encapsulant 112 a,the RDL structure 120, the passive devices 130 and the dummy items 126.The conductive vias 103 are disposed laterally aside the die 110. Theencapsulant 112 a encapsulates sidewalls of the die 110 and theconductive vias 103 and may further encapsulate a portion of the firstsurface FS of the die 110. The dummy items 126 are attached to thepolymer layer PM1 through the adhesive layers 124 a. The passive devices130 are electrically bonded to the redistribution layer RDL2 of the RDLstructure 120. The top surfaces of the dummy items 126 are higher thanthe top surfaces of the passive devices 130. Some of the dummy items 126may formed on edge portions of the RDL structure 120, some of the dummyitems 126 are formed on middle portions and center portions of the RDLstructure 120 surrounding the opening OP.

FIG. 4A to FIG. 4I are cross-sectional views illustrating a method offorming a package structure according to some other embodiments of thedisclosure. Like elements are designated with the same reference numbersfor ease of understanding and the details thereof are not repeatedherein.

Referring to FIG. 4A, in some embodiments, after the RDL structure 120is formed, a stencil 222 is placed onto the RDL structure 120. Thestencil 222 is different from the stencil 122 illustrated in FIG. 1G. Insome embodiments, the stencil 222 only has openings 123 b for exposingthe redistribution layers RDL2 and portions of the polymer layer PM2adjacent to the redistribution layers RDL2, and does not have theopenings 123 a (FIG. 1G). A first printing process is performed usingthe stencil 222, so as to apply flux material 125 onto the RDL structure120 exposed by the stencil 222.

Referring to FIG. 4A and FIG. 4B, after the flux materials 125 areapplied into the openings 123 b, the stencil 222 is removed. A pluralityof passive devices 130 are mounted on the RDL structure 120 byelectrically bonding the connectors 128 to the redistribution layersRDL2. The mounting process is substantially the same as those describedwith respect to FIG. 1H, which is not described again here. Similar tothe foregoing embodiments, a portion of the flux material 125 is reactedduring reflow process, and the flux residue is remained between thepassive device 130 and the RDL structure 120 to serve as the fillinglayer 125 a.

Referring to FIG. 4C, a stencil 222′ is placed on the RDL structure 120for a second printing process. The stencil 222′ may be the same as ordifferent from the stencil 222. The stencil 222′ has openings 123 b′exposing the passive devices 123 on the RDL structure 120. The size ofopening 123 b′ may be substantially the same as or larger than the sizeof the opening 123 b. If the size of the opening 123 b′ is the same asthat of the opening 123 b. A same stencil may be used for the first andsecond printing processes.

The second printing process is performed to apply a protection material225 on the RDL structure 120 exposed by the stencil 222′, so as to coverthe passive devices 130. In some embodiments, the protection material225 covers (e.g., completely covers) the top surfaces and sidewalls ofthe passive devices 130. In some embodiments, the protection material225 may be the same as or different from the flux material 125.

Referring to FIG. 4C and FIG. 4D, the stencil 222′ is removed, and acuring process is performed to cure the protection material 225, therebyforming a protection layer 225 a. In some embodiments, the curingprocess may cause the shape change of the protection material, but thedisclosure is not limited thereto. As shown in FIG. 4D, the protectionlayer 225 a cover top surfaces and sidewalls of the passive devices 130and sidewalls of the filling layer 125 a. An interface IF may be existedbetween the flux material 125 a and the protection layer 225 a.

Referring to FIG. 4E and FIG. 4F, in some embodiments, a third printingprocess is performed to form dummy items 226 a on the RDL structure 120.Referring to FIG. 4E, a stencil 322 is placed on the RDL structure 120,the passive devices 130 are covered by the stencil 322. The stencil 322has openings 123 a′ for exposing portions of the top surface of thepolymer layer PM2 of the RDL structure 120. The locations of theopenings 123 a′ are substantially the same as those of those of theopenings 123 a (FIG. 1G). Thereafter, the third printing process isperformed using the stencil 322 to apply dummy materials 226 on the RDLstructure 120 exposed by the stencil 322. The dummy materials 226 mayinclude molding compound material. The molding compound material mayinclude a base material (such as polymer material) and a plurality offillers distributed in the base material. The fillers may includesilicon oxide, aluminum oxide, boron nitride, alumina, silica, or thelike, or combinations thereof. The cross-section shape of the filler maybe circle, oval, or any other suitable shape. In alternativeembodiments, the dummy materials 226 may include a polymer material freeof fillers therein. The polymer material may include PBO, PI, BCB, orthe like, or combinations thereof. In yet another embodiment, the dummymaterials 226 may include a resin such as epoxy, but the disclosure isnot limited thereto. Other suitable materials may also be used as thedummy materials 226. In some embodiments, the dummy materials 226 may bethe same as or different from the material of the encapsulant 112 a.

Referring to FIG. 4F, a curing process is then performed to cure thedummy materials 226, so as to form a plurality of dummy items 226 a onthe RDL structure 120. The locations of the dummy items 226 a aresubstantially the same as the locations of the dummy items 126 describedin the foregoing embodiment. In some embodiments, compared to the shapeof the dummy materials 226, the shape of the dummy item 226 a may bedeformed after the curing process. For example, the top of the dummyitem 226 a may be rounded. In some embodiments, the width of the dummyitem 226 a gradually decreases from bottom to top. In some otherembodiments, other suitable processes, such as molding process may alsobe used to form the dummy items 226 a, and the dummy items 226 a may beformed to have a substantially planar top surface and substantiallyuniform width from bottom to top.

In some embodiments, the height H1′ of the dummy item 226 defined from atopmost point (or topmost surface) of the dummy item 226 to a bottomsurface of the dummy item 226 or a top surface of the polymer layer PM2is larger than the height H4′ defined from the top surface of thepassive device 130 to the top surface of the polymer layer PM2 of theRDL structure 120, and larger than the height H5′ defined from the topsurface of the protection layer 225 a to the top surface of the RDLstructure 120, but the disclosure is not limited thereto. In alternativeembodiments, the height H1′ may be larger than the height H4′ and lessthan or substantially equal to the height H5′. In yet alternativeembodiments, the height H1′ may be less than or substantially equal tothe height H4′. In other words, in some embodiments, the topmost pointor topmost surface of the dummy item 226 a may be higher than the topsurfaces of the protection layer 225 a and the passive device 130. Inalternative embodiments, the topmost point/surface of the dummy item 226a may be higher than the top surface of the passive device 130 and lowerthan or substantially coplanar with the top surface of the protectionlayer 225 a. In yet alternative embodiments, the topmost point/surfaceof the dummy item 226 a may be lower than or substantially coplanar withthe top surface of the passive device 130.

Referring to FIG. 4G to FIG. 4I, processes similar to those described inFIG. 1H to FIG. 1M are then performed to form a package structure PKG2.

Referring to FIG. 4G, a tape 132 is attached to the intermediatestructure 50′ formed in FIG. 4F. Similar to the foregoing embodiment,the dummy items 226 a lift the tape 132, such that the space between thetape 132 and the intermediate structure 50′ is in spatial communicationwith the outer atmosphere in the process chamber, thereby creating anair path allowing the air in the space between the tape 132 and theintermediate structure 50′ to flow out when the process chamber need tobe vacuumed. In some embodiments, the passive device 130 with protectionlayer 225 a thereon may also help to create the air path.

Referring to FIG. 4H, the intermediate structure 50′ is flipped upsidedown and attached to a table 134 through the tape 132. Thereafter, thecarrier 100 is released to expose the dielectric layer 102. A pluralityof openings 136 are formed in the dielectric layer 102 by, for example,laser drilling process, so as to expose the conductive vias 103. Aplasma cleaning process is then performed to clean the surfaces of thedielectric layer 102 and the conductive vias 103. In some embodiments,before the plasma cleaning process, the process chamber is vacuumed,during which the air in the space between the tape 132 and theintermediate structure 50′ may flow out through the air path created bythe dummy items 226 a and/or the passive devices 130, thereby avoidingthe above-described issues that may happen in plasma cleaning process.

In the present embodiments, the dummy items 226 a may also help toprotect the passive device 130 from the damage that may be caused by thestress from the table 134 if the dummy items 226 a are formed to behigher than the passive device 130 with protection layer 225 a (i.e.,the dummy items 226 a are more closer to the table 134 than the passivedevice 130 to the table 134) in FIG. 4F. Further, the protection layer225 a provides double protection for the passive device 130. In someembodiments, even the height of dummy item 226 a is formed to be nothigh enough in FIG. 4F, such as lower than the protection layer 225 a oreven lower than the passive device 130 (i.e., the passive device 130with the protection layer 225 a is more closer to the table 134 than thedummy item 226 a to the table 134), the passive device 130 can still beprotected by the protection layer 225 a. The protection layer 225 a mayhelp to reduce or avoid the stress being applied on the passive device130 from the table 134. In other words, the protection layer 225 aserves as a buffer layer to reduce the stress.

Still referring to FIG. 4H, a plurality of connectors 138 are formed onthe conductive vias 103 exposed by the dielectric layer 102. As such, apackage structure PKG2 is thus formed, and a singulation process may beperformed along scribe lines SL to singulate the package structure PKG2.

Referring to FIG. 4H and FIG. 4I, the singulated structure PKG2 isremoved from the table 134 and the tape 132 is removed. Referring toFIG. 4I, in some embodiments, the package structure PKG2 includes thedie 110, the encapsulant 112 a, the conductive vias 103, the RDLstructure 120, the passive devices 130, the dummy items 226 a and theconnectors 138. In some embodiments, the dummy item 226 a is in physicalcontact with the polymer layer PM2 of the RDL structure 120. Thematerial of the dummy item 226 a may be the same as the material of theencapsulant 112 a, but the disclosure is not limited thereto. A fillinglayer 125 a is formed to fill the space between passive device 130 andthe RDL structure 120, and a protection layer 225 a is disposed on theRDL structure 120 to cover the passive device 130 and/or the fillinglayer 125 a. The other structural features of the present embodiment aresubstantially the same as those described in the foregoing embodiment,which are not described again here. It is noted that, the protectionlayer 225 a and/or dummy items 226 a may also be applied in otherembodiments described herein.

FIG. 5 is a cross-sectional view illustrating a package structure PKG3according to some other embodiments of the disclosure. The embodiment ofthe FIG. 5 is similar to the foregoing embodiments, except that the RDLstructure 120 further includes dummy features.

Referring to FIG. 5 , in some embodiments, the RDL structure 120 furtherincludes a plurality of dummy pads or dummy connectors DP. The dummypads DP are formed on the top surface of the polymer layer PM2 and mayinclude a conductive material that are similar to, the same as ordifferent from those of the redistribution layers RDL1 and RDL2. Thedummy pads DP and the redistribution layer RDL2 may be formedsimultaneously or successively. In the embodiments, the dummy pads DPare electrically floating, that is, electrically isolated from theredistribution layers RDL1 and RDL2. The dummy pads DP are disposed forbonding the dummy items 126.

For example, the bonding of the dummy items 126 to the dummy pads DP mayinclude the flowing processes: in the process shown in FIG. 1G, the fluxmaterial 124 is applied onto the dummy pads DP exposed by the opening ofthe stencil. Thereafter, dummy items 126 are placed onto the dummy padsDP, during which portions of the flux material 124 may be pushed outwardto surround the dummy pad DP and/or the dummy item 126. A reflow processis then performed during which a portion of the flux material 124 may bereacted with the dummy item 126 and/or the dummy pad DP, while theunreacted flux reside may be remained to form an adhesive layer (orreferred to as a protection layer) 124 b disposed between and/orlaterally surround the dummy pad DP and/or the dummy item 126.

FIG. 6A to FIG. 6D illustrate various examples of the dummy items 126bonding to dummy pads DP.

Referring to FIGS. 6A to 6D, in some embodiments, the dummy item 126 maybe in physical contact with the dummy pads DP, and the adhesive layer124 b may cover the sidewalls of the dummy pads DP and/or the sidewallsof the dummy item 126.

FIG. 7 illustrates a cross-sectional view of a package structure PKG4according to yet another embodiment of the disclosure. The presentembodiment is similar to the foregoing embodiment, except that theencapsulant 112 a does not cover the first surface FS of the die 110.

Referring to FIG. 7 , as described above in FIG. 1B to FIG. 1F, in someembodiments, the sacrificial layer 109 may be formed to cover the entiresurfaces of the passive layer 107 and the conductive pads 106 of the die110, and the encapsulant 112 a may be formed laterally aside the die 110without covering the first surface FS of the die 110. In such anembodiment, more portions of the RDL structure may be formed to coverthe first surface FS the die 110 and laterally surrounded by theencapsulant 112 a. For example, a portion of the polymer layer PM1 isformed to cover and physically contact portions of the top surfaces ofthe passivation layer 107 and the conductive pads 106. The conductivevia V1 may merely penetrate through the polymer layer PM1 to connect tothe conductive pads 106. The other features of the package structurePKG4 are substantially the same as those of the package structure PKG1described in FIG. 1M, which are not described again here.

In accordance with some embodiments of the disclosure, a packagestructure includes a die, an encapsulant, a redistribution layer (RDL)structure, a passive device, and a plurality of dummy items. Theencapsulant laterally encapsulates the die. The RDL structure isdisposed on the die and the encapsulant. The passive device is disposedon and electrically bonded to the RDL structure. The plurality of dummyitems are disposed on the RDL structure and laterally aside the passivedevice, wherein top surfaces of the plurality of dummy items are higherthan a top surface of the passive device.

In accordance with alternative embodiments of the disclosure, a packagestructure includes a die, an encapsulant, a RDL structure, a passivedevice, a protection layer and a plurality of dummy items. Theencapsulant encapsulates sidewalls of the die. The RDL structure isdisposed on the encapsulant and the die. The passive device is disposedon and electrically bonded to the RDL structure. The protection layercovers a top surface of the passive device. The plurality of dummy itemsare disposed on the RDL structure and laterally aside the passive deviceand the protection layer.

In accordance with some embodiments of the disclosure, a method offorming a package structure include: forming an intermediate structureby the following processes: attaching a die to a dielectric layer;forming an encapsulant to encapsulate sidewalls of the die, forming aRDL structure on the encapsulant and the die, bonding a passive deviceto the RDL structure, and disposing a plurality of dummy items on theRDL structure and laterally aside the passive device; placing a tape onthe intermediate structure, wherein the dummy items lift the tape, suchthat a space between the tape and the intermediate structure is inspatial communication with outer atmosphere in a process chamber;attaching the intermediate structure to a table through the tape,wherein a portion of the tape is in contact with both of the dummy itemsand the table; and forming a conductive terminal penetrating through thedielectric layer.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the disclosure.Those skilled in the art should appreciate that they may readily use thedisclosure as a basis for designing or modifying other processes andstructures for carrying out the same purposes and/or achieving the sameadvantages of the embodiments introduced herein. Those skilled in theart should also realize that such equivalent constructions do not departfrom the spirit and scope of the disclosure, and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the disclosure.

What is claimed is:
 1. A package structure, comprising: a die; anencapsulant, laterally encapsulating the die; a redistribution layer(RDL) structure, disposed on the die and the encapsulant; a passivedevice, disposed on and electrically bonded to the RDL structure; and aplurality of dummy items, disposed on the RDL structure and laterallyaside the passive device, wherein top surfaces of the plurality of dummyitems are higher than a top surface of the passive device.
 2. Thepackage structure of claim 1, wherein the plurality of dummy items areattached to the RDL structure through adhesive layers respectivelydisposed between the plurality of dummy items and the RDL structure. 3.The package structure of claim 2, further comprising a filling layerdisposed to fill a space between the passive device and the RDLstructure, the filling layer laterally surrounds a connector of thepassive device and a conductive pillar of the RDL structure, wherein amaterial of the filling layer is the same as materials of the adhesivelayers.
 4. The package structure of claim 1, wherein the plurality ofdummy items are in contact with a top surface of a polymer layer of theRDL structure.
 5. The package structure of claim 1, wherein theplurality of dummy items are bonded to dummy connectors of the RDLstructure.
 6. The package structure of claim 5, further comprising anadhesive layer at least covering sidewalls of the dummy connectors. 7.The package structure of claim 1, further comprising a protection layercovering sidewalls and a top surface of the passive device.
 8. Thepackage structure of claim 1, wherein the encapsulant furtherencapsulates a portion of a front surface of the die, and the RDLstructure comprises: a polymer layer over the encapsulant and the die,and a redistribution layer penetrating through the polymer layer and theencapsulant to be electrically connected to a conductive pad of the die.9. A package structure, comprising: a die; an encapsulant, encapsulatingsidewalls of the die; a RDL structure, disposed on the encapsulant andthe die; a passive device, disposed on and electrically bonded to theRDL structure; a protection layer, covering a top surface of the passivedevice; and a plurality of dummy items, disposed on the RDL structureand laterally aside the passive device and the protection layer.
 10. Thepackage structure of claim 9, further comprising a filling layer,disposed to fill a space between the passive device and the RDLstructure, and laterally surround a connector of the passive device,wherein the protection layer further covers a sidewall of the fillinglayer and a sidewall of the passive device.
 11. The package structure ofclaim 10, wherein an interface is existed between the protection layerand the filling layer.
 12. The package structure of claim 10, whereinthe protection layer and the filling layer comprises a same material.13. The package structure of claim 9, wherein the plurality of dummyitems are in contact with a top surface of a polymer layer of the RDLstructure.
 14. The package structure of claim 9, wherein the pluralityof dummy items comprise a molding compound.
 15. A method of forming apackage structure, comprising: forming an intermediate structure,comprising: attaching a die to a dielectric layer; forming anencapsulant to encapsulate sidewalls of the die; forming a RDL structureon the encapsulant and the die; bonding a passive device to the RDLstructure; and disposing a plurality of dummy items on the RDL structureand laterally aside the passive device; placing a tape on theintermediate structure, wherein the dummy items lift the tape, such thata space between the tape and the intermediate structure is in spatialcommunication with outer atmosphere in a process chamber; attaching theintermediate structure to a table through the tape, wherein a portion ofthe tape is in contact with both of the dummy items and the table; andforming a conductive terminal penetrating through the dielectric layer.16. The method of claim 15, wherein the dummy items are formed to behigher than the passive device, and a portion of the tape is in contactwith the passive device and separate from the table.
 17. The method ofclaim 15, wherein bonding the passive device and disposing the dummyitems comprise: forming a flux material on a conductive pillar of theRDL structure; forming an adhesive material on the RDL structure;bonding the passive device to the conductive pillar, wherein the fluxmaterial facilitates the bonding between the passive device and theconductive pillar; and attaching the dummy items to the RDL structurethrough the adhesive material.
 18. The method of claim 17, wherein theflux material and the adhesive material are formed of a same materialthrough a same printing process.
 19. The method of claim 15, furthercomprising: forming a protection layer on the RDL structure to coversidewalls and a top surface of the passive device.
 20. The method ofclaim 15, wherein disposing the dummy items on the RDL structurecomprises: performing a printing process to form a plurality of dummymaterials on the RDL structure; and performing a curing process on theplurality of dummy materials to form the dummy items.